QS tiles background mod.[1/2]

Option to set the color of QS background
and the color when pressed.
ported to vanir 4.4

PS2 & 3: provide overriding method to support system themes and
remove unnecessary "reset colors" code - primedirective
PS4: make sure it only observes quicksettings and not ribbon yet

NUCLEARMISTAKE WAZ HERE
PS5: Move all settings gets into a place that only happens ONCE per setup
     !Overridden ==> Custom... the meaning of the system setting was opposite
         that of the meaning of the checkbox, and that's NOT OK.

Change-Id: I8e5f980de4a150795455e30262c609230dcd410f